1. Field of the Invention
This invention relates to a method for making a wall in the ground, whereby a plurality of drilling elements is drilled into the ground next to each other and at a distance from each other and a hardening liquid is injected into the earth loosened by this drilling.
2. Discussion of the Related Art
Such methods are substantially used for manufacturing water protection walls or water retention walls, for example, temporary waterproof protection walls for cellar constructions, in particular at locations where it is not allowed to vibrate or drive damming plates or such into the ground.
Thereby, it is known to use drilling rods as drilling elements which are provided with spiral-shaped blades over a well-defined height.
By means of a drilling device, three or more such drilling elements are drilled into the ground simultaneously, whereby adjacent drilling rods are rotated in opposite sense in order to keep the torque on the drilling device low.
After having drilled the ground loose, the drilling rods are screwed out of the ground.
During screwing and unscrewing of these drilling rods, cement slurry is injected into the loosened ground which is blended with the latter over the entire diameter of the loosened ground.
In this manner, pillars are formed of a relatively soft mixture of loose ground and cement slurry, the diameter of which is larger than the diameter of the drilling rods and is as large as the diameter of the blades. With drilling rods of a diameter of, for example, 25 cm, a pillar with a diameter of, for example, 60 cm is obtained.
The such formed adjacent pillars overlap each other by approximately 15 centimeters.
After unscrewing the drilling rod from a pillar, a metal I-profile is lowered into this pillar, after which the mixture of ground and cement slurry may harden.
After this hardening, the metal profiles provide for strength and the hardened mixtures for the watertight-ness. It is then possible to excavate next to the formed wall.
In grounds which are hard to blend, such as in tough clay, clods may be created in the mixture which may lead to leaks after hardening.
In such grounds which are hard to blend, and in particular in clay-like grounds, the drilling rod has to be screwed and unscrewed several times, and a large amount of cement slurry has to be injected.
This has as a result that the total volume of the ground to be blended is increased by 70% or more. The surplus ground which is created thereby and which has the consistency of a thick slurry, flows over the building site and is collected in a pit in order to be transported off after stiffening.
This transporting off causes high costs, in particular when the method is applied in city agglomerations.
Besides, according to the environmental rules of many countries, such ground is polluted ground, as a result of which the dumping thereof is expensive.
Together with the transported-off ground, also a large amount of cement is lost. So, for example, with a daily production of 100 m3 ground and cement mixture, daily at least 40 to 70 m3 of ground comprising 12 to 16 tons of cement will be transported off.
The present invention aims at a method which does not show the aforementioned disadvantages and which involves a minimum of ground and lost hardening material to be transported off and which allows to manufacture a leak-free wall also in grounds which are not easy to blend.
According to the invention, this aim is achieved in that as drilling elements, drilling pipes are brought into the ground which comprise a cylindrical tubular element which is open at one extremity and carries teeth and which is provided with at least one channel-shaped profile which opens at the extremity of the tubular element which is provided with teeth and in that by means of this profile, during drilling, a hardening liquid is injected into the ground uprooted by the teeth, whereby the drilling pipes are left in the ground during the hardening of the mixture of ground and hardening liquid formed by the teeth.
Contrary to the aforementioned known method, only circular pillars of ground, mixed with hardening liquid, are formed, and the drilling pipes remain in the ground.
In the profile of a tubular element, preferably an injection pipe is provided and hardening liquid is injected through this injection pipe.
After reaching the desired depth, this injection pipe can be removed, whereby, during withdrawal of the injection pipe, preferably hardening liquid is injected, too.
Drilling pipes may be used, the tubular element of which comprises two profiles on its outside which are situated diametrically opposite each other and in which an injection pipe is provided through which, during bringing them into the ground, hardening liquid is injected, which injection pipe is removed from the profile after the drilling pipe has reached the desired depth.
Moreover, the profiles may be provided with a groove at the outside, whereby the drilling pipes are stopped in such position that they are situated with a profile opposite to each other, after which a connecting panel is slid with its longitudinal edges into the profiles, situated opposite to each other, of two adjacent drilling pipes, whereby the connecting profile extends through the groove at the outside of the profiles.
In this form of embodiment, the distance between the drilling pipes can be relatively large.
A connecting panel may be used, the longitudinal edges of which are provided with a profile and fit in the profiles at the tubular elements.
An injection pipe may also be provided along the connecting profile, through which hardening liquid is injected, for example, when bringing in this connecting panel, whereby, after bringing in, this injection pipe is withdrawn from the ground. Preferably, two adjacent drilling pipes are drilled into the ground in opposite sense.
Drilling pipes may be used, the teeth of which are that large and are placed in such a manner that they blend ground with the injected hardening liquid up to 15 to 30 mm at the inside of the tubular element and approximately 40 to 50 mm at the outside of the tubular element.
The invention also relates to a drilling element formed by a drilling pipe and clearly destined for application with the method according to any of the preceding forms of embodiment.